Every week the game is updated with more exciting things and new boss fights. It is all free because of the ads in the game. Without ads we can’t keep the online arena server alive as it cost a lot to maintain it and to use it. Also by watching ads we can continue to add new boss fights to the game. Without ads, there is no game development budget and the game can’t add anything new.
If you don’t want to see ads in the online arena. Please help support the game and buy the no ads purchase in the shop. It’s the cheapest purchase in the game. Or buy any other purchase and this will also disable the ads. For example if you buy the Fenixaro purchase, you will get the no ads for free.